1. Field of Invention
The present invention pertains to the art of washing machines and, more particularly, to a vertical axis washing machine including a rotating/tipping agitator.
2. Discussion of Prior Art
As environmentally friendly washing machines are more and more demanded by the public, manufacturers are faced with the problem of designing machines that use less water and, by extension, less energy to perform a washing cycle without causing a degradation in the quality of machine performance. One approach is to offer horizontal axis machines which use less water to thoroughly soak articles of clothing rotated within an inner tub. While this approach is an effective solution, it does not address the concerns of many consumers which, either by custom, or by spatial requirements, desire vertical axis machines.
Vertical axis machines have certain advantages over their horizontal axis counterparts. For example, vertical axis machines have fewer sealing requirements and therefore are less prone to leakage, and are arguably easier to load. For at least these reasons, many users find it advantageous to have a top loading machine. However, washing machine manufacturers find themselves faced with governmental regulations requiring more energy efficient laundry machines. In view of these new requirements, manufacturers have sought out designs which can make a vertical axis washer more energy efficient, while still being economically feasible. To this end, manufacturers have proposed various profile designs for agitators in attempting to more effectively move the wash load, or to vary the cycle to promote a better mixing of laundry. While each of these methods are effective to a degree, improvements are still deemed necessary.
The water level in a standard vertical axis machine cannot be lowered without negatively impacting wash performance. In addition, to effectively perform a wash cycle, the agitator must generate movement within the wash load as clothes tend to rest on the bottom of the machine and move in unison with the agitator. Tests on low water use machines have shown that some form of vertical motion is required to cause the wash load to turn over, thereby enabling each article of clothing to receive a corresponding amount of washing action.
Accordingly, a design that incorporates both the traditional oscillatory/rotating motion, coupled with a vertical or tipping motion, will enable a washing machine to use less water without negatively affecting wash quality. The prior art actually has many examples of machines that utilize a combination horizontal/vertical movement of clothing. However, most are either very complicated, possessing multiple failure points, or are not readily retrofittable to current designs, thereby not defining a cost effective solution. Accordingly, based on at least these reasons, there is a need in the art for a rotating/tipping agitator arrangement which will provide the necessary motion to clothing being washed in the tub of a vertical axis washing machine, while enabling the washing machine to utilize lower amounts of water, and be both easily serviceable and retrofittable into current designs.